Process for the production of camphor from isoborneol



Patented Nov; 16, 1926.

UNITED STATES HERMANN GAMMAY, or srur'rennr, GERMANY.

PROCESS FOR THE PRODUCTION OF GAMPHOR FROMIlISOBOBNEOL.

No Drawing.

This. invention relates to a process for the production of camphorfrom isoborneol. It is known to produce camphor from isoborneol by means of chromic acid. According to the known processes the entire amount of chromic acid required for the oxidation of a batch of isoborneol is added, all at once,

- inform of a very dilute solution, to the re:

. the reaction in large excess, the camphor first ,formed is further oxidized and the yield and action mixture. A great disadvantage of this procedure isthat, due to the fact that the chromic acid is present at the beginning of (finality of the camphor product are thus unavorably influenced to a very substantial extent. Another disadvantage is that, due to the great dilution of the reactionmixture, large-reaction vessels are required.

Accordin phor is obta ned in almost quantitative yields and of an excellent quality from isoborneol if to the isoborneol in subdivided foimmixe'd with Water, chromic acid solution is carefully added while stirringuntil the-melting point of 'camphor is reached. The reaction at first proceeds very slowly for which rea son a few. percent of a non-oxidizable solvent preferably are added at the beginning.

-As soon'as oxidation commences the reaction mixture becomes warm. Theaddition of, chromic acid solution is continued until the highest temperature admissible for the oxidation" is attained.- Thereupon the supply is shut off and'the reaction mixture is cooled. After this coolin has been efl'e'cted chromic acid solution is a ded again; This procedure is repeateduntil a sample exhibits the re-' quired melting point;

' sulfuric acid in either case .beingsuflicient to liberate from bichromate the quantity of chromic acid requlre'd for the .oxidation' of the isoborneol and thereupon gradually in-.

troducing bi'chromate solution mtovthe 'mixture. of sulfuric acid,-water and isoborneol in the same manner as the chrom c acid so' lution is' introduced into the mixture of water and isoborneol as described above.

to the present invention cam-' Applicationfiled January 2a, 1926. Serial No. 84,512;

A special advantage of the process, which resembles titration, undoubtedly liesain the fact that the chromic acid is always applied n a very dilute state and is never present in large excess.

' E sample.

1500 kgs. isoborneol are stirred "up with 2000-3000 kgs. water and about kgs.-benzole orits homologues or benzine are added.

Thereupon a solution of 1000 kgs, sodium bichromate in admixture with 1350 kgs. sulphuric acid of 66 B. and 2700 kgs. water are gradually introduc'edin the above-described manner, for a period of from 6 to 8 hours.

What I claim is:

1. Process for the production of camphor by the oxidation of isoborneol by means of chromic acid which comprises gradually applying chromic acid to'a mixture of isoborncol in subdivided form and water while agitating the mixture, the rate of application of the chromic acid being not substantially greater'than the rate at which the chromic acid is consumed by the oxidation reaction.

2. Process for the production of camphor as defined in claim 1 in which the chromic acid is applied to aninitially cold mixture of isoborneol and water and the application of chromic acid and agitation are continued until the temperature of the mixture reaches the melting point of camphor.

3. Process for the roduction of camphor as defined in claim 1 in which the mixture of isoborneol and water contains a relatively small proportion of'a non-oxidizable solvent of isoborneol.

4: Process for the production of camphor as defined in claim 1 in which the mixture of isoborneol and water contains sulfuric acid in quantity s'ufiicient to liberate the quantity of chromic acid required for the oxidation from bichromate and bichromate solution is slowly added to the mixture duringnthe agitation; I

testimony whereof I aflix my signature HERMANN GAMMAY. 

